Artificial lighting in schools : a benchmark study on the energy consumption and quality of artificial lighting in Maltese schools

Abstract

In the past, schools in Malta used to rely exclusively on natural light given that they were predominantly used during the day. However, modern exigencies where classrooms are being used all year round and even outside school hours have rendered schools dependent on artificial lighting to satisfy these needs. Moreover, natural lighting although very important for a student’s performance and physiological needs, unfortunately cannot be found in equal measure in all areas of the school and all day long. In this context, the research presented in this dissertation studies the current use of artificial lighting in schools and investigates whether any correlation exists between the power and energy consumption of the artificial lighting being utilised in schools and the quality of lighting (illuminance, colour temperature, colour rendering index, visual comfort, glare, etc.) present. Based on the results obtained this research aims at providing guidelines to obtain the best quality artificial lighting for schools in Malta with the least energy consumption possible. To satisfy the intended aims and objectives, the research makes use of two approaches. A qualitative analysis whereby questionnaires were distributed amongst primary school teachers or kindergarten educators of various schools to understand their experience and perception of the artificial lighting present in schools, and site visits to log actual values for the illuminance and power consumed within the respective classrooms. Based on the results obtained from the two approaches, statistical methods were then applied to investigate trends between the quality of the artificial lighting present in Maltese schools and the power and energy consumption. The type of lighting technologies present in classrooms was also investigated. Many schools, around 78% were found still using fluorescent tubes to light up their classrooms, while only 22% use LED lighting. Although the fluorescent tubes give a good illuminance value, these are quite inefficient compared to LED technology. Based on the measured lighting power density and illuminance value measured amongst all classrooms fluorescent tubes were found to consume 279% more power per 100Lux compared to LED Lighting. Furthermore, results indicate that students whose classroom utilize LED lighting fixtures technology have better visibility and experience a higher level of visual comfort compared to students whose classrooms still utilize fluorescent tubes. In terms of lighting power required to ensure visual comfort, results show that students are totally satisfied with the lighting provided in the classroom, if the lighting power is 380 Watts. Finally, an interesting correlation was found between the mean artificial lighting illuminance and the visibility, visual comfort and uniformity of artificial lighting, whereby results show that when the illuminance increases, there is an overall (linear) positive improvement in the responses given to these three lighting characteristics.